Overview and perspectives of sustainable recycling of anaerobic digestion biogas residue of organic solid waste in China
摘要
Biogas residue, also known as digestate, is the solid by-product of anaerobic digestion, rich in organic matter and nutrients. In China, various types of biogas residue display distinct physical, chemical, biological, and toxicological properties depending on their feedstock and treatment processes. Conventional disposal methods, such as landfilling, can result in nutrient loss and pose environmental risks. This review provides a comprehensive evaluation of the major resource recovery pathways for biogas residue: thermochemical transformation technologies (pyrolysis and hydrothermal carbonization) and composting. These processes offer sustainable solutions for converting biogas residue into value-added products, including biochar, compost, and hydrochar. Additionally, the review outlines future strategies for optimizing digestate management, with a focus on tailoring treatment approaches to specific residue types, streamlining processing chains, and integrating front-end production with back-end waste management. These recommendations aim to improve resource efficiency, mitigate environmental impacts, and promote sustainable development within the framework of a circular economy.